Campaigners have condemned proposals to build properties for 409,000 new households in the West Midlands as "environmental vandalism".

The Campaign for the Protection of Rural England claims the Government plans to push through a massive house-building programme, threatening green belt and destroying the countryside.

But the accusations were rejected by the Department for Communities and Local Government, which said building would be concentrated on existing industrial or commercial land.

The row follows the publication of a study which showed the demand for accommodation was set to shoot up, partly as a result of a massive increase in the number of people living alone.

Rural authorities have warned that some of the proposals would damage the environment and place too much strain on local services.

The West Midlands Regional Assembly, a body representing councillors, businesses and bodies such as trade unions, has been given the task deciding where the new homes will be built.

Its proposals will be based on a Government study published this year which warned the number of single-person households in the West Midlands was set to increase from 649,000 to 969,000 between 2003 and 2026.

This was significantly higher than previous estimates and means the total number of households will increase from 2,193,000 to 2,602,000, up by 409,000. Birmingham alone will see an increase of 98,000 new households. But much of the strain will fall on rural areas.

Worcestershire will become home to 51,000 new households while Shropshire will see 24,000 extra households. In Hereford-shire, the number of households will increase by 19,000.

Some of the growth could be accommodated by making better use of existing properties, but thousands of new homes will also need to be built.

Herefordshire has been told it must build anything between 16,000 and 25,000 new homes.

But in a submission to the Regional Assembly, Hereford-shire Council warned this would "risk damaging the environment of the county, would potentially result in a less sustainable pattern of development and would not be feasible without significant investment in new infrastructure."

The CPRE warned the Government to prepare for opposition on the same scale as in the South-east, where protesters have accused Ministers of planning to concrete over the green belt.

Peter Langley, vice chairman of West Midlands CPRE, said extra houses and other development associated with them could consume up to 40 square miles of land over the next 25 years.

He said: "The West Midlands needs more affordable homes but swamping the market with greenfield land and playing fast and loose with the region's long-established green belts won't achieve that; it's a form of environmental vandalism.

"The Regional Assembly must stick to its guns and resist Government pressure to open the floodgates to new housing."

But a spokesman for the Department for Communities and Local Government said: "The number of households is not the same as the number of dwellings.

"It will be up to the regional assembly to determine the best way to meet this demand."